Dramatic Irony
When the audience or readers know more than the character does. eg in a horror film where the audience knows the killer has gone into the closet where the girl is just about to enter- the audience knows the killer is there, but the girl doesn’t;
Dramatic Soliloquy
Used to reveal a character’s thoughts and feelings. Are usually delivered while the character is on their own, speaking to the audience.
Duologue
Where two people are performing a scene - like a monologue- except there are two people on stage instead of one